Longitudinal genotype analysis and quantification of hepatitis C virus in haemophilia patients receiving interferon-α therapy

Haemophilia patients have a high prevalence of hepatitis C virus (HCV) infection because of the use of unsterilized clotting factor concentrates. Six major genotypes of HCV have been distinguished so far, with epidemiological evidence suggesting that genotypes 1-3 are common in the indigenous UK and US populations. The aim of this study was to analyse the changes in viral load and composition of the HCV quasispecies in haemophilic patients receiving therapy with interferon-α (IFN-α) using the four major methods currently available for HCV genotyping. The most consistent genotype results were obtained using restriction fragment-length polymorphism (RFLP) analysis when compared with the DNA sequence analysis, and showed that the dominant genotype can change in patients with mixed genotype infections treated with IFN-α. This study indicates the difficulties in studying this group of patients with mixed HCV genotype infections, and that frequent sampling is necessary, together with viral load measurement to monitor response to IFN-α therapy. © 1996 Blackwell Science Ltd.